The present invention relates to an improved method for fabricating a molded body, and also pertains to an improved apparatus for the performance of the inventive method.
A method and apparatus of the aforementioned type are known from U.S. Pat. No. 1,960,573. The blank formed of clay material is placed in a mold closed at least at five sides, and continuous hollow spaces of the blank are disposed perpendicular to the mold floor. Openings arranged in the mold floor serve for blowing through a hot gas for swelling the blank. In this publication there are mentioned different measures in order to prevent caking of the swollen blank in the mold box. Thus, among other things, there is mentioned that there can be rolled into the surface of the blank sand or the mold of the mold box can be strewn with sand. The mentioned measures however do not fulfil the purpose, since such thin sand layers become lost in the expanding blank and lose their effectiveness. The markedly expanding blank bears, under pre-stress, at the mold of the mold box. During cooling of the blank in the mold box the latter contracts more intensely than the swollen blank and fixedly clamps the same. Consequently, on the one hand, there is impossible mold release of the expanded blank even when using a sanded mold or sanded blank. Quite to the contrary, the tendency exists that the swollen blank will distort or damage the mold box.